1. Field of the Invention
The present invention relates to a manufacturing apparatus of a plugged honeycomb structure for forming plugging portions at opening ends of cells of a honeycomb structure, and a manufacturing method of the same.
2. Description of the Related Art
There is an increasing need to remove, from an exhaust gas, fine particles and harmful substances included in the exhaust gas from an internal combustion engine, a boiler or the like, in consideration of an influence on the environment. In particular, a regulation on the removal of the fine particles (hereinafter sometimes referred to as the particulate matter (PM)) exhausted from a diesel engine tends to be strengthened in Europe, the United States and Japan, and a honeycomb structure is used in a collecting filter for removing the PM.
Examples of the filter used for such a purpose include a honeycomb filter using a plugged honeycomb structure in which a plurality of cells constituting flow paths of a fluid is partitioned by partition walls. The structure includes plugging portions which alternately plug one opening end and the other opening end of the plurality of cells. According to such a honeycomb filter, when an exhaust gas G1 is allowed to flow into the cells from the end face of the filter on an exhaust gas inflow side and the exhaust gas G1 passes through the partition walls, particulates in the exhaust gas are collected by the partition walls, so that it is possible to discharge a purified gas G2 from which the particulates have been removed, from the end face of the filter on a purified gas outflow side.
Moreover, as a manufacturing method of the above plugged honeycomb structure, there is suggested, for example, a method including the steps of attaching an adhesive sheet or the like to one end face of a honeycomb structure (an unfired dried ceramic article); making holes only in portions of the adhesive sheet or the like corresponding to the cells to be plugged (plugged cells) by laser processing or the like using image processing to form a mask; immersing, into a slurry (a ceramic slurry), the end face of the honeycomb structure to which the mask has been attached; filling the slurry into the plugged cells of the honeycomb structure to form the plugging portions; subjecting the other end face of the honeycomb structure to a step similar to the above step; and performing drying and firing to obtain the plugged honeycomb structure (e.g., see JP-A-2001-300922).
However, according to the above method of making the holes in the adhesive sheet and immersing, into the slurry, the honeycomb structure provided with this adhesive sheet as the mask, an operation time is required for leveling the slurry for the immersion, which factors into cost increases. Moreover, the leveling is a very delicate step, the outer peripheral portion of the structure thickens or thins owing to even slight deviation, and it is therefore difficult to obtain a uniform plugging depth. A leveling precision agrees with a depth precision, and hence additional labor and time are necessary for the leveling step. Moreover, the film needs to be bent so that the immersed end is not made dirty, but it is not easy to appropriately bend the film. Moreover, it is not easy to peel the bent film attached to the side surface of the structure after the plugging, which hinders automation steps.